Dielectric Properties of Electrical Insulating Liquids for High Voltage Electric Devices in a Time-Varying Electric Field

The motivation to improve components in electric power equipment brings new proposals from world-renowned scientists to strengthen them in operation. An essential part of every electric power equipment is its insulation system, which must have the best possible parameters. The current problem with mineral oil replacement is investigating and testing other alternative electrical insulating liquids. In this paper, we present a comparison of mineral and hydrocarbon oil (liquefied gas) in terms of conductivity and relaxation mechanisms in the complex plane of the Cole-Cole diagram and dielectric losses. We perform the comparison using the method of dielectric relaxation spectroscopy in the frequency domain at different intensities of the time-varying electric field 0.5 kV/m, 5 kV/m, and 50 kV/m. With the increasing intensity of the time-varying electric field, there is a better approximation of the Debye behavior in all captured polarization processes of the investigated oils. By comparing the distribution of relaxation times, mineral oil shows closer characteristics to Debye relaxation. From the point of view of dielectric losses at the main frequency, hydrocarbon oil achieves better dielectric properties at all applied intensities of the time-varying electric field, which is very important for practical use.

Enhancement of Flotation Performance of Oxidized Coal by the Mixture of Laurylamine Dipropylene Diamine and Kerosene

Conventional hydrocarbon oil cannot adhere effectively to oxidized coal, resulting in a low yield of clean coal. In this study, a high-speed homogenizer was used to emulsify LDD (laurylamine dipropylene diamine) and kerosene, which enhanced the flotation efficiency of oxidized coal. The flotation results showed an increase from 4.12% (only kerosene) to 23.33% (emulsified oil). An increase in contact angle indicated that the mixture reagent can increase the hydrophobicity of coal particles, which is attributed to the adsorption of LDD onto the coal particle surface and the decrease of the oil droplet A lower surface tension of LDD allows it to produce a stable layer of froth than the layer generated by kerosene alone.

FLOATING TANK FOR TRANSPORTING OIL AND HYDROCARBONS FOLLOWING A MARITIME DISASTER

Storage of recovered oil and oily water is an important issue when it comes to maritime disasters, being a significant factor of the overall operation. Using large storage vessels is not always an option especially when the vessel is close to the shore. Currently, floating or non-inflatable tanks made of composite textile materials are used worldwide for the storage of the water/hydrocarbon mixture, regardless of the area of action (maritime or fluvial). The research carried out so far by INCDTP specialists, which consists in modelling, simulation and numerical analysis of various constructive forms and devices, led to the conclusion that for the making of a floating tank for storing water/hydrocarbon/oil mixtures, the best solution for its construction is represented by textile materials woven from high-tech yarns (p-aramid and polyamide 6.6) covered with polyurethane. The experimental model of the floating tank for the transport of oils and hydrocarbons in case of disaster was designed by INCDTP specialists and consists of five experimental models of floating materials (made of five variants of covered textile structures) and assembled in collaboration with specialists from SC CONDOR SA, in the form of a floating storage tank. The storage tank that has been created will be tested on the ground first, in order to perform all gravimetric and quality measurements

Petroleum sulfonates of the karpatol trademark as the most effective surfactants for acting on the formation of producing wells

Experimental studies and pilot test results of developed stimulation technologies with petroleum sulfonate indicate economic benefits of the use of Karpatol achieved due to significant reduction in interfacial tension surfactant-hydrocarbon (oil, condensate, petrol); increase of residual oil displacement factor, destruction of water-oil emulsions, partial permeability build-up of contaminated rock samples, advanced permeability of surfactants in nonuniform permeable and hydrophobic strata, influence on the rheology of viscous oils, improvement of wells development after stimulation, high technological efficiency of stimulation technologies using Karpatol, increase of production index after treatment.

Self-assembly of chiral foldamers with alternating hydrophilic and hydrophobic side chains into acid-sensitive and solvent-exchangeable vesicular particles

It is difficult for the same molecule to self-assemble into stable vesicular particles in water and aliphatic hydrocarbon (oil), respectively. Here we demonstrated that chiral oligo(methylene-p-phenyleneethynylene)s with alternating hydrophilic and...

Spatial localization of charged molecules by salt ions in oil-confined water microdroplets

Cells contain more than 100 mM salt ions that are typically confined to dimensions of 5 to 10 micrometers by a hydrophobic cellular membrane. We found that in aqueous microdroplets having the same size as cells and that are confined in hydrocarbon oil, negatively charged molecules were distributed rather uniformly over the interior of the microdroplet, whereas positively charged molecules were localized at and near the surface. However, the addition of salt (NaCl) to the microdroplet caused all charged molecules to be localized near the oil-water interface. This salt-induced relocalization required less salt concentration in microdroplets compared to bulk water. Moreover, the localization became more prominent as the size of the microdroplet was reduced. The relocatization also critically depended on the type of oil. Our results imply that salt ions and different hydrophobic interfaces together may govern the local distribution of charged biomolecules in confined intracellular environments.

Electrical Discharge Machining of Oxide Nanocomposite: Nanomodification of Surface and Subsurface Layers

The work is devoted to the research of the changes that occur in the subsurface layer of the workpiece during electrical discharge machining of conductive nanocomposite based on alumina with the use of a brass tool. The nanocomposite of Al2O3 + 30% of TiC was electroerosively machined in a water and hydrocarbon oil. The process of electrical discharge machining is accompanied by oscillations that were registered by diagnostic means. The obtained surface of the samples was researched by the means of scanning electron microscopy and X-ray photoelectron spectroscopy. The observed surface and subsurface changes provide grounding for the conclusions on the nature of processes and reactions that occur between two electrodes and nanomodification of the obtained surfaces that can be an advantage for a series of applications.